Apparatus for forming concrete piles in the ground



May 23, 1933. c "rm- 30 1,910,939

APPARATUS FOR FORMING CONCRETE FILES IN THE GROUND Filed April 27 1928llllllllllllllu 5'2: mrllllllll Inventor. Alberr C. Tircomb Patented May23, 1933 a a -M E 1 PATENT OFFICE I ALBERT QTI'ICOMB, or NEWTON,MASSACHUSETTS mums FORFORMING conenn'rn. ruins IN THE GROUND Applicationfiled A ri1g27,

This invention relates to. improvements in method and apparatus forforming concrete piles in the groundfand' the object thereof is toprovide a novel method and apparatus which will more efficiently producethehole to receive the concrete which forms the pile and whichwillenable conerete piles to be properly constructed at a minimunrcostof material and labor.

In "usualprocesses of forming concrete piles inthe groundythe holetoreceive the concrete is formed by driving into the ground a tubularforming member having a conical cast iron point having substantially thesame maxinnun diameter as the diameter of the driving forniand providedwith a shank which extends into, and substantially"fits, the lower endof the "driving "lorI'n. VVhenhthe driving form has been sunk untilthefpoint encounter-5a rigidmw terialfor when the resistance to furtherdriving exceedsa predetermined minimum force, the driving form is filledwith concrete and tlielorm pulled out,additional concrcte being pouredin, it necessary, during the extractionpf the form.

fIn soniecases previously castconical con crete points havebecnemployed, and in others conical concrete points armored with afnietallie shell, or expensiveeast steel pointshave been used i When inthe use of such apparatus the drivingf form isforced through a stratumeontaining stones of considerable size the clinical metallic or other"points are frequently broken and great, difiiculty; there afterencountered in properly sinking the form to a suflicient depth to givethe pilea suitable foundation.

a driving point of the charaeter specified, having the same diameterasthatof the driving form, isdriven through a stratum of this characterthe formj Wlll become wedged betweendarge pieces rock so that it canbewithdrawn 1928, Serial No. 273,219.

only with great difiiculty and in many instances requiring the use of awater jet to shift the location oftherock. Again, concrete piles arefrequently i e-Q quired to be driven among old wood piles and where aconical point, such as above described, of approximately the same sizeof the driving form, employed and driven among such old piles, theremoval ofthe form, after it has been filled with concrete, has provedvery diflieultandsome times inipossiblei I Ly Y i The present inventionis designed to overcome these and other difliculties' which areencountercdin the production of con cretepiles inthe ground. iThe'method offorming concrete piles in the grormd, inaccordance with myinvention, comprises driving into thelground a preparatory pile havingat its lower end a detachable, substantially fiat, infrangible metallicdriving head of greater area than the area of the lower end of saidform, then filling the chamber of the form, to a greater or less degree,withconcrete and withdraw etrating heads a suitable foundation for thepile may be made upon strata of sand, or other material, which would notproperly supporta :pile having as va footing the conical penetratingpoint. t a

By employing a flat penetrating point of this character, whiclris oflarger diameter than the diameter ofthe driving form, the

driving form can be readily withdrawn after having been filled withconcrete, thereby affecting a great saving in time and labor over usualmethods.

Usual types of cast iron conical points for driving forms heretoforeemployed are of very considerable weight approximating one hundredpounds each. In the present invention the penetrating head, which is inthe form of a substantially flat infrangible steel plate preferablyhaving a peripheral flange surrounding the lower end of the drivingform, is much lighter, such flat penetrating heads weighingapproximately forty pounds having been successfully employed withoutbreakage under conditions which caused frequent breakage of the heaviercast iron conical heads. Y

The production of such fiat penetrating heads is relatively inexpensiveand a considerable saving in cost of transportation is effected wherelarge numbers of concrete piles are being formed.

Such flat heads are of greater effective area than the conical heads andgive a greator bearing surface which in some soils permits the use of amuch shorter pile, thus decreasing the cost of thepile. Furthermore, theflat surface of the head in many soils gives a better bearing, forexample, where piles are driven to'hard material which cannot bepenetrated by the conical point more than aninch or two, the bearingsurface on the hard material is very limited, where as with the flatsurface of the penetrating head embodying the present invention thewhole area of the head is in contact with the hard material thus givinga greater faetor of safety.

A preferred form of apparatus embodying the present invention isillustrated in the accompanying drawing, in which,

Fig. l is arvertical sectional View of a driving form having a flatmetallic, preferably steel, penetrating head thereupon and sunk into theground;

Fig. 2 is a detail View of the same showing a packing between thejunction of the lower end of the driving form and a flat penetratinghead, the packing being onclosed. within the flange of the head whichsurrounds the lower end of the driving form;

Fig. 8 is a sectional view on line 3-3 Fig. 2, viewed downwardly, aportion of the wall of the. form being broken away to illustrate thepreferred form of packing which is in the form of a coiled rope packedwith grease; V

Fig. 4 is a detail vertical sectional view of a concrete pile formed inaccordance with the present invention, the fiat penetrating head forminga footing for the pile;

Fig. 5 is a detail vertical sectional view of a slightly modified formof substantially diameter or area than that of the lower end of thedriving form. The penetrating head 2 is provided with means presenting ashoulder to prevent undue lateral displacement relatively to the lowerend of the driving head. In the particular form illustrated the drivinghead has an upwardly extending peripheral flange 3 which surrounds thelower end of the driving tube.

' In the use of the apparatus described the penetrating head 2 may beplaced upon the soil at the spot where the pile is to be driven, thedriving form 1 superimposed thereupon within the peripheral flange 3,and a suitable block or head placed upon the upper end of the drivingform, and the form forced downwardly by blows, hydraulic pressure, orotherwise, as is usual.

It is found in actual practice that where stones or rocks areencountered by the driving head, the engagement with such rocks is suchthat they will be generally forced laterally out of the path of thedriving form.

Inasmuch as the head 2 is of reater area than the area of the lower endof the driving form, the rocks will thus be forced laterally asuiiicient distance to prevent wedging against the wall of the drivingform so that the driving form may be readily withdrawn after the formhas been driven to such depth that the head engages an impenetrablemedium, or engages a stratum affording the required degree of resistanceto further driving.

When the form has thus been driven down it is filled with concrete andwithdrawn in the usual manner, the concrete, after withdrawal of theform, filling the hole produced by the apparatus above described. Thehead. which is, of course, detachable from the driving form, remains atthe lower end ofthe hole and forms a flat footing for the concrete withthe peripheral flange enclosing the lower end of the concrete pile. Thisflat footing provides a more even distribution of the strains imposedupon the pile when a structure is superimposed upon it and consequentlyprovides a much firmer foundation than that which would be provided by aconical point, the effective area of the supporting portion of which isfremeans shall be provided to prevent accumulation of water within thedriving form dur ing the driving thereof as such water would otherwisehave to be removed before the concrete is poured into the pile in orderto insure a proper consistency of concrete at the lower end of, orthroughout, the pile.

Thepresent invention permits a proper water-tightseal between the lowerend of the driving form and the head to be employed as the sealingmechanism will be properly retained within the peripheral flange whichsurrounds the lower end of the driving form.

Apacking of fibrous material containing a water-repellant substance isemployed. A preferred packing, which is illustrated in Figs. 2 and 3,comprises a coil of rope 4L thoroughlyimpregnated with heavy grease, therope being coiled in a flat spiral within the flange 3 and preferablyextending beneath the lower end of the driving member as illustrated inFig. 2. 7

Other forms of substantially flat penetrating heads are illustrated inFigs. 5 and 6.

In the construction illustrated inFig. 5 the substantially flat plate,which forms the penetrating head, has an annular flat portion 5 whilethe central portion 6 is convexedly curved downwardly.- The plate isprovided with a peripheral flange 3 to enclose the lower end ofthedriving member as above described. p

i In the construction illustrated in Fig. 6

the substantially flat penetrating head presents an annular flat portion7 and a central, slightly conical,portion 8. In this form, as intheother, the J'enetrating head is pro vided with the peripheral flange3 which encloses the lower end of the driving form. In both of theseconstructions the lower end of the driving form rests upon the flatannular portion of the head.

It has been found in practice that where substantially flat infrangiblesteel plates are employed for penetrating heads, plates of considerablyless thickness than the thickness of the wall of the driving form may besuccessfully used.

As a matter of fact, steel plates having a thickness of three-eighthsinch and provided with peripheral flanges have been successfullyemployed. as penetrating heads for driving forms the walls of which arethreefourths inch in thickness, and driving forms having such heads havebeen successfully driven in soil conditions in which it was quiteimpossible to drive similar forms havwhich 'illustmtes a concrete pileproduced 3 after a. driving form had been sunk through thesoilcondition, comprising a fill A of several feet, witha sand stratum Btherebeneath varying in thickness, with a clay stratum C therebeneath.In driving the form for this pile: rocks D were encountered which wereforced laterally from the path of the driving form by thewlarger head ofthe pile. When the flat driving head had reached the stratum B of sanditpresented a sufficient area properly to support the pile, where withusual conical points the supporting area in certain portions of the sandstratum was of insuflicient thickness to provide suitable resistancerequiring the use of a pile several feet longer than that which wasrequired for piles having the flat footing provided by the flatpenetrating head embodying the present invention.

It has been found that the cost of constructing concrete piles withforms having flat steel penetrating heads is considerably tion.Furthermore, the delay occasioned by damage to the driving formincreases the ultimate cost of the pile. Where the present inventionisemployed no such breakage of the penetrating head has been found tooccur under any conditions of service.

It will be understood that the embodiment ofthe invention disclosedherein is of an illustrative character and is not restrictive, and thatthe term substantially flat is in tended to embrace not onlyconstructions such as are illustrated in the drawing, but otherequivalent constructions adapted for the same purpose and operating inalike manner.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is:

1. An apparatus for forming concrete piles in the ground comprising acylindrical driving form, a substantially flat steel penetrating head,of greater area than that of the lower end of said driving form,engaging the lower end of said driving form and having a peripheralflange enclosing said lower end and spaced apart therefrom, and ayieldable packing of fibrous material containing a water-repellantsubstance within said flange.

2. An apparatus for forming concrete piles inthe ground comprising acylindrical driving form, a substantially flat steel pene- ALBERT C.TITCOMB.

